Electromagnetic well service tool



April 29,' 1969 c. F. FARMER I l 3,441,307 y ELECTEOMAGNETIQ WEEE SERVICE TooL v Filed July ,25,v 1967A United States Patent O 3,441,307 ELECTROMAGNETIC WELL SERVICE TOOL Charlie F. Farmer, San Angelo, Tex., assignor of fifty percent t Ray E. Dorrance, San Angelo, Tex. Filed July 25, 1967, Ser. No. 655,959 Int. Cl. B66c 1/06; E21b 31/06; E21c 19/02 U.S. Cl. 294-655 8 Claims ABSTRACT 0F THE DISCLOSURE A yfishing tool for recovering magnetically attract-a-ble objects from within a well bore, body of water and the like which tool includes a cable supported sealed extensible electromagnet means telesco-pngly, sealingly and normally nestingly received within a cable guided nonm-agnetic outer shield means comprising a downwardly opening member normally supported by the electromagnet means and wherein the electromagnet means preferably includes `a downwardly depending magnetizable probing means to assist in magnetically attracting magnetizable objects buried beneath loosely consolidated shale, dirt, silt and the like.

The present invention relates to an electromagnetic tool for recovering magnetically attractable objects from wi-thin a cased well, uncased well bore, body of water, and the like. More particularly, the present invention relates to an electromagnetic well service tool adapted to retrieve iish from within a well bore by magne-tically grappling the fish and generally nesting the `fish within a nonmagnetic lshield during 'withdrawal of the well service tool from within the Well,

It is an objec-t of the present invention to provide a novel construction for an electromagnetic well service tool.

`Another object of the present invention is to provide a novel construction for an electromagnetic Iwell service tool which is provided with means generally sealing an electromagnet within the tool from the adverse affects of water, production lluid, silt, and the like within a well bore or body of water.

A further object-of the present invention is to provide a novel construction for an electromagnetic grappling tool which includes a cable supported generally sealed cylindrical shield means containing lan electromagnet means generally and sealingly protruding from the lower end thereof which shield means is telescopically and normally nestingly received within a generally nonmagnetic tubular outer shield means concentrically disposed about the electromagnet means and :slidingly but sealingly received lby a cable supporting the electromagnet means.

Still another object of the present invent-ion is Ito provide a novel construction for an electromagnetic grappling tool wherein an electromagnet normally nestable within a generally nonmagnetic shield may be selectively projected from within the nonmagnetic shield to facilitate magnetically grappling magnetizable objects resting at a depth somewhat beneath the maximum travel, i.e., at rest position, of -the nonmagnetic shield.

Still another object of the present invention is to provide a novel construction for an electromagnetic grappling tool which may be operated from a coaxial supportelectrical conduit cable or separate parallel support and electrical conductor cables.

Still another object of the present invention is to provide a novel cons-truction for an electromagnetic grapple tool wherein the electromagnet means of the tool is provided with a downwardly projecting magnetizable probing means adapted to assist in magnetically grappling 3,441,307 Patented Apr. 29, 1969 lCe magnetizable objects partially or Wholly buried 'beneath loosely consolidated shale, silt, and the like.

These together With other objects and advantages which will become subsequently apparent reside in .the details of construction and operation as more fully hereinafter described and claimed, reference being had to the accompanying drawings forming a part hereof, wherein like numerals refer to like parts throughout, and in which:

FIGURE 1 is a medial vertical cross-sectional view of an exemplary embodiment of an electromagnetic tool shown operatively positioned within a cased well bore and further showing `the relative position of subassemblies during lowering of t-he tool into the bore;

FIGURE 2 is a medial vertical cross-sectional view, 'analogous to the view of FIGURE l, but showing the relative position of subassemblies of the tool during the magnetic recovery of an object buried beneath loosely consolidated shale, silt, etc.; and

FIGURE 3 is a fragmentary medial vertical crosssectional view of the exemplary tool of FIGURES 1 and 2 further showing the relative position of subassemblies of the tool subsequent to the pick-up of a magnetically attractable object and further showing lthe object nestingly received within the shield means during withdrawal of Ithe electromagnet tool from the well.

Referring now to the drawings in greater detail and particularly an exemplary embodiment of the invention illustrated in FIGURE l, it will be seen .that an electromagnetic tool indicated generally at 10 comprises an outer tubular, generally cylindrical shield means 12 slidingly and sealing guided upon a coaxial support cable indica-ted at 14. Telescopically and normally nestingly received Within vthe tubular outer shield means l12 is an electromagnet means indicated generally at 16 which is supported by the support cable means 14. As will bccome apparent hereinafter the electromagnet means -16 includes an inner electromagnet shield means indicated generally at 18 which cooperates, in a manner -to be described hereinafter to hermetically seal an electromagnet contained therein.

The outer shield means 1-2 includes an elongated tubular generally cylindrical body portion 20 provided with a downwardly opening end W-all indicated generally at 22. The upper end of the outer shield body por-tion 20 is closed with a removably engaged end bell 24 preferably provided with an interiorly threaded downwardly depending ;skirt portion 2'6 threadably and sealingly received on a complementary threaded portion 28 of the upper end of the body portion l20. The end bell 24 -is provided with 4a centrally and vertically disposed through bore indicated generally at 30 sized Vso as to freely slidingly receive the support lcable means 14. The end bell 24 is also provided with an upper wiping seal means indicated generally at 32 adapted -to provide a wiping seal about the cable support mea-ns 14 to generally .preclude the ent-ry of fluid into the in-terior of the outer shield means 12 about the Vsupport cable means 14. Toward this end, the end bell 24 includes an exteriorly threaded -upstanding packing receiving boss 34 within which is received packing material 36 extending circumferen-tially around about the c-a-ble support `14 and compressed thereagainst by :a packing compressing andretaining bonnet nut 38. The shield body portion 20 further includes a lower Wiping seal means indicated generally at 40 disposed intermediate of the ends of Ithe body portion 20 on the inner wall thereof and comprising an inwardly projecting annular ring 42 having an annular packing receiving g-roove therein within which is retained a packing member 44 such -as comprising an O-ring or the like. The lower end of the outer shield body portion 20 is provided with an inwardly projecting annular flange 46, which in fact delines ythe opening 22, which flange 46 cooperates, in a manner, to become clear to arrest downward travel of the electrom-agnet means 16. In addition, the end bell 24 further includes a through bore indicated at 48, and disposed laterally of the through bore 30 so as not to interfere with the passage of `the support cable means `14 ltherethrough. The through bore 48 comprises a portion of a venting means including a vent valve 50 received therein to facilitate .the discharge lof fluid which may inadvertently iind its way past the wiping seal means 32 and 40 into the interior of the upper portion of the outer shield means 12.

Refer-ring now in further detail to the electromagnet means 1'8 it is seen that it includes an upper end bell 52 which terminates in a support cable means securing means indicated generally at 54 which includes an upwardly Iand exteriorly threaded boss 56 about `which is threadably received a support cable means compression and securing nut 58 provided with a centrally disposed Iaperture including an annular groove for the reception of an O-ring *60 to hermetically seal the support cable means 14 in its passage therethrough. In the exemplary embodiment illustrated it will be .seen that the support cable means 14 is of coaxial type `wherein a supporting steel cable 15, such las formed of `stranded wire sheathed in some suitable manner, includes an interiorly disposed, and generally non-supporting, electrical conduit 17. It will thus be appreciated that by appropriately tightening the threadably received nut 58 the lower end of the support cable will be compressed between the boss 56 'and the nut 58. The electrical conduit 17 passes downwardly through a suitable through bore in the end bell 52 and is operatively connected to an electromagnet 62 provided with suitable electrical insulation 64 `and removably secured to the end bell 52 by an electromagnet core 66 secured to the end bell S2 by the inner shield `18 threadably .and sealingly secured at its upper end as at 68 to the end bell 52 and adjacent `its lower end as indicated at 70 to the magnet core 66. The electromagnet core 66 includes an annular flange 72, either formed with or pressed onto the main body of the core 66 so as to provide a stop member coacting with the annular ring 42 and the flange 46 to limit upward and downward longitudinal travel of `the electromagnet means 16, The inner shield 18, as `well as the end bell 52 and nut 58 `are preferably of a nonmagnetic met-al. However, the magnet core 6'6 is generally of an alloy which although magnetizable generally does not retain a significant `degree of magnetism when energizing current to the electromagnet 62 Iis not owing.

The downwardly projecting portion of the electromagnet core 6'6 is preferably provided with a removably received tubular generally cylindrical probing means 74 comprising an annular ring 76 threadably received on the lower end of the core member 66 and including a p1urality of downwardly Aprojecting integral iingers 78 adapted to probe, in a manner to be described, beneath loosely consolidated shale, dirt, silt and the like to retrieve magnetically attractable objects. Thus, it will be understood that the probing means 74 is of -a metallic alloy functionally analogous to the magnet core l66.

The electromagnet 62 preferably operates on a 32 volt electrical current of 200 amps., for example, although it will be appreciated that the input to the electromagnet 62 through the elect-rical conduit 17 may vbe suitably altered for various operating conditions. Although not indicated heretofore, Ithe body portion of the outer shield means 12 is generally nonmagnetic for reasons which will become clear hereinafterl Referring now lto the operation and utilization of the exemplary embodiment 10 of an electromagnetic tool illustrated herein, and first referring to FIGURE 1, it will be seen that the tool 10 is shown as being lowered into a well bore including a casing 80 of a generally magnetic nature. For purposes of illustration a deposit of loosely consolidated shale, silt or the like 82 is shown at the lower end of the Vcasing from within which a magnetically at-tractable object or sh 84 is to be retrieved. lAs seen in FIGURE 2 when the support cable means 14 has been paid out sufficiently to permit the lower end of lthe outer shield means 12 to come to rest outer shield means 12 and the inner shield means 18 begins and .the inner shield means 18 slidingly `and sealingly moves downward-ly within the annular ring 42 whereby the magnet core means 66, such as provided with the probing means 74, -moves from its normal nested position within `the nonmagnetic shield 12 to its extensible position, as seen in FIGURE 2, wherein the electromagnet 62 may be suitably energized through the electrical conduit 17 to magnetically grapple the object 84. It will also be appreciated that in the `absence of the probing means 74 the lower portion of the magnet core 66 is extensible from within the outer shield means 12 to facilitate the magnetic grappling of an object to be retrieved.

As seen in FIGURE 3, lift has once again been applied to the support cable means 14 thereby moving the electromagnet means 16 upward relatively to the outer shield means 12 whereby the stop member 72 comes to `rest against the underside of the annular ring 42 thereby assuming the relative position shown `in FIGURE l whereby the inner shield means 16 picks up the outer shield means i12. Furthermore, it will be seen that with the electromagnet `62 still energized the retrieved object, or iish 84, is nestingly received within the lower portion of the generally non-magnetic body portion of the outer shield means 12 so as to generally preclude inadvertent magnetic securement of the object 84 and/or probing means 74 to the generally magnetic well casing 80 during retrieval of the tool 10 with the object 84 magnetically secured to the lower end thereof. Upon surfacing of the tool 10 it is merely necessary to discontinue the iiow of energizing current to the electromagnet 66 to permit release of the object 84.

`In addition, although not shown therein, it will be appreciated that `the electromagnet core 66, with or without the probing means 74 thereon, is extensible from within the outer shield means l12 a distance generally comparable `lto the distance between the ange 72 and the lower end of the magnet core 66 or the lower end of thel fingers 78 on the probe means 74.

What is claimed as new is as follows:

1. A iishing tool for recovering magnetically attractable objects from within a well bore, body of water and the like, which tool comprises a cable supported hermetically sealed generally elongated electromagnet means, a generally nonmagnetic downwardly openin g outer shield means slidingly received on a cable supporting said electromagnet means, said outer shield means telescopically and normally nestingly receiving said electromagnet means therewithin, said electromagnet means being partially extensible from the lower end of said outer shield means to permit the magnetic retrieval of an object, upper and lower stop means adapted to limit the upward and downward movement of said electromagnet means relative to said outer shield means and said outer shield means being provided with upper and lower wiping seal means to generally seal the interior of said outer shield during relative movement between said outer shield and said electromagnet means.

2. The combination of claim 1 wherein said electromagnet means comprises an elongated magnet core, an electromagnet adjacent the upper end of said magnet core, a generally cylindrical inner shield means surrounding said electromagnet and having its lower end removably secured to Said magnet core, said inner shield having its upper end removably secured to a fastening means removably securing said electromagnet means to a support cable.

3. The combination of claim 2 including a magnetizable probing means removably secured to the lower end of said magnet core, said probing means including at least one downwardly projecting linger adapted to probe beneath loosely consolidated deposits generally overlying an object to be recovered.

4. The combination of claim 2 including vent means adjacent the upper end of said outer shield means to vent uid which has inadvertently entered the interior of said outer shield above said electromagnet means.

5. A iishing tool for recovering magnetically attractable objects from within a well bore, body of water and the like, which tool comprises a cable supported hermetically sealed generally elongated electromagnet means, a generally nonmagnetic downwardly opening outer shield means slidingly received on a cable supporting said electromagnet means, said outer shield means telescopically and normally nestingly receiving said electromagnet means therewithin, said electromagnet means being partially eX- tensible from the lower end of said outer shield means to permit the magnetic retrieval of an object, upper and lower stop means adapted to limit the upward and downward movement of said electromagnet means relative to said outer shield means, said outer shield means being provided with upper and lower wiping seal means to generally seal the interior of said outer shield during relative movement between said outer shield and said electromagnet means, said upper seal means comprising an annular seal member operatively positioned about a support cable passing through an upper generally closed end of said outer shield means and said lower seal means comprises a lower annular seal member carried by the interior of said outer shield means intermediate the ends thereof, said lower annular seal member sealingly and slidingly engaging said electromagnet means.

6. The combination of claim 5 wherein said electromagnet means comprises an elongated magnet core, an electromagnet adjacent the upper end of said magnet core, a generally cylindrical inner shield means surrounding said electromagnet and having its lower end removably secured to said magnet core, said inner shield having its upper end removably secured to a fastening means removably securing said electromagnet means to a support cable.

7. The combination of claim 6 including a magnetizable probing means removably secured to the lower end of said magnet core, said probing means including at least one downwardly projecting finger adapted to probe beneath loosely consolidated deposits generally overlying an object to be recovered.

8. The combination of claim 5 including vent means adjacent the upper end of said outer shield means to vent fluid which has inadvertently entered the interior of said outer shield above said electromagnet means.

References Cited UNITED STATES PATENTS 2,539,435 1/1951 Kirby 294-6-5.5 2,582,602 1/ 1952 Paysinger 294-655 2,613,980 10/1952 Hawkins 294-655 EVON C. BLUNK, Primary Examiner.

U.S. Cl. X.R. 294-861; 166-99 

